There is a friend of a friend who needs a computer and since I have a spare laptop, I told him I would give it to him. The problem is that it has years of old personal data that I want erased.

Here are some of the steps I have taken.

Backup
The first step is to backup all your data onto an external hard drive. I used SyncToy for this task.

Delete User Accounts
Next, I signed into an Administrator account and chose to delete my Standard User account. It offered to save the files onto my desktop in a folder. You also need to make sure you are not signed into the account you are trying to delete.
I then did copy the folder it made onto an external hard drive – now I had two backup copies of my data.

Wipe the Free Space
Under Tools, it will allow you to Wipe the Free Space. You get to choose how many passes it will make. This will take a long time, so just let it run over night. The expert Steve Gibson says that three passes is all you need.

Install and run Macrium Reflect
This will do an image backup of your clean system and will be available if necessary.